Hearing Loss in Patients with Alopecia Areata

Melanocytes in the Ear May also Be Target for Alopecia Areata Related Inflammation

Several studies have suggested that follicular melanocytes may be one of the important targets of the autoimmune process involved in alopecia areata. It appears that T cells targeting melanocytes in the hair follicle are partially responsible for hair loss. A 2009 study by Trautman and colleagues showed that melanocytes are reduced in established areas of alopecia areata. It is well known that non-pigmented and white hairs often regrow first in alopecia areata - a further indication of the different effects of the immune system on pigmented hairs vs non-pigemented hairs.

Given that melanocytes have such an important role in hearing, several studies have investigated whether the inflammation that is part of alopecia areata might also affect hearing. In mouse models, it is known that mice lacking melanocytes due to the mutations in microphthalmia-associated transcription factor (which is important for the development of melanocytes) have deafness in addition to white fur, microphthalmia.

Second, when we consider other diseases affecting melanocytes, it’s clear that hearing loss is often present. For example, hearing loss is often found in patients with vitiligo - an autoimmune disease affecting melanocytes. 4-37 % of patients with vitiligo have abnormalities of the auditory system. Other human diseases with defects in melanocytes are also known to be associated with hearing loss. This includes Waardenburg syndrome and Vogt-Koyanagi-Harada syndrome.

The exact role of melanocytes in the ear is not entirely clear.

Sounds travels into the ear in the ear canal and hits the ear drum. The three bones in your middle ear called the malleus, incus, and stapes carry vibrations from your ear drum to the cochlea. Your cochlea contains hair cells with tiny hair-like projections called stereocilia. These structures convert sound vibrations into neural impulses.

Studies have shown that melanin may have key functions in the hearing system as a result of its semiconductive properties, responsiveness to phonic, acoustic and electrical stimulation, and ability to convert energy states into molecular rotation and vibration. Moreoever, it appears that melanocytes in the ear have many more functions. They are essential for survival of hair cells, the normal functioning of the stria vascularis and cochlea, the development of endocochlear potentials, as well as for tightly controlled ion and fluid gradients between endolymph and perilymph. Melanocytes also help to resist free radical damage. It’s clear that we need melanocytes in the ear!

Ucak et al 2014

In 2014, researchers set out to evaluate if audiological abnormalities were increased in patients with alopecia areata compared to controls. The authors studied 51 patients with AA and compared findings to 51 healthy controls. Autoscopic and audiometric examinations of both ears were performed in patients and controls.

Results showed that sensorineural hypoacusis was found in 55% of patients with alopecia areata (28 of 51 or 54.9%) compared to 25 % of controls. This sensorineural hypoacusis was asymptomatic and limited to high frequencies. Of the 28 patients with alopecia areata who had hearing loss, 6ix of these 28 patients showed unilateral minimal hearing loss (>30 dB) at high frequencies only (4000–16 000 Hz), while 22 showed bilateral minimal hearing loss (>30 dB) at high frequencies only (4000–16 000 Hz). Hearing loss was more common in those with long standing disease and those with more advanced disease. Overall, sensorineural hypoacusis was significantly more frequent in AA patients than controls (P = 0.002).

Shaheen et al 2015

In 2015, Shaheen et al performed a small study of 20 AA patients and 20 controls.The authors study showed a significant presence of sensorineural hearing loss in AA patients compared to controls. This hearing loss had a direct correlation with the disease severity, duration and the recurrence of attacks.

The Shaheen et al study was one of the few studies to really show an association between disease duration and hearing loss. Most other studies have not shown this.

Like the Ucak study, Shaheen showed an association between disease severity and hearing loss. Many other studies have not shown this relationship.

Kocak et al 2017

The study was comprised of 51 patients with an AA diagnosis in the Dermatology Clinic of our hospital (the AA group), and a further 50 healthy volunteers who attended the hospital for routine health screening. In the audiological examination, pure tone audiometry and transient-evoked otoacoustic emission (TAOE) levels were checked within a quiet cabin by an expert audiologist. The pure tone threshold level was determined as 250- 20 000 Hz for air conduction level in each ear, and 500-4000 Hz for bone conduction level. The transient-evoked otoacoustic emission level measurement was performed to 1, 1.4, 2, 2.8, 4 kHz frequencies in both ears

In the AA and control groups, TOAE did not show significant differences at 1 kHz or 1.4 kHz frequencies. TOAE 2, 2.8 and 4 kHz frequencies were significantly lower in the AA group than in controls.

In pure tone audiometry, air conduction hearing thresholds did not show significant differences at 1000, 2000, 6000, 9000 or 11 200 Hz frequencies in the AA and control groups. Air conduction hearing thresholds in the AA group were significantly higher than in the control group at 250, 500, 4000, 8000, 10 000, 12 500, 14 000, 16 000 and 20 000 Hz frequencies. Bone conduction hearing thresholds in the AA group were significantly higher compared to the control group at 500, 1000, 2000 and 4000 Hz frequencies.

Overall the authors concluded that statistically significant sensorineural hearing loss was observed in patients with alopecia areata compared to controls.

Erdoğan HK et al 2019

In 2019, authors from Turkey evaluated hearing tests in 48 patients with AA and 39 healthy volunteers. All the patients had audiometric examinations performed using a pure-tone audiometer. Pure-tone thresholds for both ears were evaluated at frequencies of 250-8000 Hz for air conduction. Overall, sensorineural hypoacusis was found in 18.8% of AA patients and 10.3% of control subjects but this was not statistically significant (p=0.422). When the authors compared hearing thresholds for both ear for frequencies, there were not any significant differences between AA patients and controls (p>0.05). Overall, the authors concluded that there was no difference in terms of hearing loss between AA patients and healthy controls.

Lee et al 2019

A 2018 meta-analysis sought to determine the health conditions that are increased or decreased in patients with alopecia areata. Lee and colleagues from South Korea evaluated 87 published studies. A 3.57 fold increased risk of hearing abnormalities was identified among patients with alopecia areata compared to controls. We reviewed this study together in 2021 (See “Comorbidities in Patients with Alopecia Areata”)

Ma S-H et al 2020

Authors from Taiwan performed a large population based cohort study to evaluate whether patients with alopecia areata were at increased risk for hearing loss. The authors included 5002 patients with AA and 50 020 controls.

Overall, 33 patients with AA developed HL, with an overall rate of 77.46 cases per 100 000 person-years, whereas 75 individuals without AA had HL, with an overall rate of 17.53 cases per 100 000 person-years.

After adjustment for potential confounders, patients with alopecia areata had about a 4 fold increased risk of developing hearing loss (adjusted hazard ratio, 4.18; 95% CI, 2.78- 6.31) compared to controls. interestingly, this included all types of hearing loss including an increased risk of developing conductive HL, sensorineural HL, and other types of HL. This included specifically a 3.7 fold increased risk of sensorineural hearing loss, a 17.32 fold increased risk of conductive hearing loss and 2.5 fold increased risk of mixed patterns.

Ertugrul G et al 2021

Authors from Turkey compared hearing tests in thirty-two AA patients and 35 sex- and age-matched healthy volunteers. They did not find any differences between these two groups.

****UPDATED 2023***

Lien KH et al 2023

In a 2023 study (see , authors performed a systematic review using five case-control studies and one cohort study. The meta-analysis showed AA patients had significantly higher mean differences in pure tone hearing thresholds at 4000 Hz and 12000-12500 Hz. The meta-analysis also found a three fold increased odds for SNHL among patients with AA (OR 3.18; 95% CI 2.06-4.89). The hearing loss was most marked at 12000-12500 Hz. However, among 250 to 8000 Hz, the range which most sounds of daily conversations occur, only 4000 Hz showed significant difference in the author’s meta-analysis. All in all, the authors here concluded that alopecia areata is associated with an increase of SNHL, especially at high frequencies.

Conclusions

All in all, there is an association between alopecia areata and sensorineural hearing loss, especially at high frequencies. In some studies, hearing loss was more common with greater degrees of hair loss and longer duration but this was not found in all studies.

REFERENCES

Erdoğan HK, Acer E, Hakkı A, Bulur I, İncesulu A, Pınarbaşlı Ö, Bilgin M: Evaluation of hearing with pure-tone audiometry in alopecia areata patients. Turkderm Turkish Archives of Dermatology and Venereology 2019;53:19-23.

Ertugrul G, Ertugrul S, Soylemez E: There is no evidence of cochlear and vestibular melanocyte damage in patients with alopecia areata. Int J Clin Pract 2021;75:e14040.

Koçak HE, Filiz Acıpayam A, Acıpayam H, Çakıl Erdoğan B, Yıldız NY, Küfeciler L, Elbistanlı MS, Kaya KH: Is there a relationship between melanocytes and sensorineural hearing loss? Clinical evaluation of 51 patients with alopecia areata. Clin Otolaryngol 2018;43:705-710

Lee S et al. Comorbidities in alopecia areata: A systematic review and meta-analysis. .J Am Acad Dermatol. 2019 Feb;80(2):466-477.e16.

Ma S-H et al. Association of Sensorineural Hearing Loss in Patients With Alopecia Areata: A Nationwide Population-Based Cohort Study.m JAMA Dermatol. 2020 Nov 1;156(11):1262-1264.

McGinness J, Corry P, Proctor P. Amorphous semiconductor switching in melanins. Science 1974; 183: 853–855.

Shaheen MA, Matta M, Rahman TTA, Refaat N: Hearing threshold abnormalities in patients with alopecia areata. The Egyptian Journal of Otolaryngology 2015;31:267-272.

Trautman S, Thompson M, Roberts J, Thompson CT. Melanocytes: A possible autoimmune target in alopecia areata. J Am Acad Dermatol 2009; 61: 529–530.

Ucak H et al. Audiological abnormalities in patients with alopecia areata. J Eur Acad Dermatol Venereol. 2014 Aug;28(8):1045-8.